Why the flu vaccine can not give you the flu

Influenza vaccination prevents millions of influenza-related illnesses and deaths each year, but vaccination rates are low for many reasons.

During the 2018-2019 influenza season, the Centers for Disease Control and Prevention reported that approximately 45% of American adults had received the influenza vaccine. Although it's an 8% increase over 2017-2018, it falls well below the national target of 70% of US adults getting vaccinated against the flu.

One of the common myths that make people avoid influenza vaccine is that they think the vaccine will give them the flu. But that's just not true. The virus contained in the vaccine is not active and an inactive virus can not transmit the disease. What is true is that you can feel the effects of your body's immune response, but that does not mean you have the flu.

I am a nurse teacher experienced in promoting public health and I often hear this and other myths. Here are the facts and explanations behind them.

Inactive virus

Influenza, or influenza, is a common but serious infectious respiratory disease that can lead to hospitalization or even death. The CDC estimates that during a "good" influenza season, about 8% of the US population could catch the flu. That's about 26 million people.

Every year, the flu season is different and the flu virus also affects people differently. Pneumonia is a dangerous complication of the flu. It can happen when your body is struggling to fight the flu. This is particularly dangerous in older adults, young children and those with poor immune systems, such as those receiving chemotherapy or receiving a transplant.

Historically, millions of Americans catch the flu each year, hundreds of thousands are hospitalized and tens of thousands of people die from complications related to the flu. During the 1918 influenza pandemic, one-third of the world's population – about 500 million people – was infected with the flu. Since then, the science of vaccines has radically changed the impact of infectious diseases.

Vaccination is the cornerstone of influenza prevention. The CDC recommends that all persons 6 months of age and older who do not have contraindications to the vaccine should be vaccinated against influenza.

And since the polio vaccine will not give polio to children, the flu vaccine will not cause the flu. This is because the flu vaccine is made from inactive strains of the flu virus, which are not able to cause the flu.

That said, some people may feel sick after receiving the flu shot, which may suggest that they are sick.

However, feeling under bad weather after an influenza vaccine is actually a good thing. This can be a sign that the immune response of your body is working. Here's what happens: when you receive the flu vaccine, your body recognizes the inactive influenza virus as a foreign invader. This is not dangerous your immune system develops antibodies that attack the influenza virus when they are exposed later. This natural immune response can cause some people to develop mild fever, headaches, or muscle aches. These side effects can be confused with the flu, but in reality it is probably the body's normal response to vaccination.

And the good news is that these natural symptoms are short-term side effects compared to the flu, which can last much longer and is more serious. It is estimated that less than 2% of people who get the flu shot will develop fever.

In addition, people often confuse the flu with a cold or stomach flu. Flu symptoms may include fever, chills, sore throat, runny or stuffy nose, body aches, fatigue, and headaches. Cold symptoms may be similar to those of the flu, but they are usually less severe. The intestinal flu, or gastroenteritis, can be caused by several bacteria or viruses. Symptoms of gastroenteritis include nausea, vomiting and diarrhea.

Pre-tour exhibitions and mismatches

Some people get the flu after receiving an influenza vaccine, but that is not the case. This can happen for several reasons.

First, they could have been exposed to the flu before the shot. It can take up to two weeks after the influenza vaccine to develop complete immunity. Therefore, if you get the flu during this time, it is likely that you have been exposed to the flu before vaccination or before your total immunity has developed.

Secondly, depending on the strain of influenza virus you are exposed to, you can still get the flu even if you have received the vaccine. Each year, the flu vaccine is created to best match the strain of influenza virus circulating. Therefore, the effectiveness of the influenza vaccine depends on the similarity between the circulating virus in the community and the killed viruses used to make the vaccine.

If there is a close match between the two, the effectiveness of the influenza vaccine will be high. However, if there is no close match, the effectiveness of the vaccine could be reduced. Nevertheless, it is imperative to note that even though there is no close match between the circulating virus and the virus used to make the vaccine, it will still reduce the severity of influenza symptoms and will also help to prevent complications related to the flu.

Bottom Line: You can not get the flu by getting the flu shot. As someone who has cared for many people with the flu, I urge you to get vaccinated.

Libby Richards, Associate Professor of Nursing, Purdue University

This article is republished from The Conversation under a Creative Commons license. Read the original article.